Augustine of Hippo

O Lord, "they shall walk in the light of Thy countenance." "They shall rejoice in Thy name all the day" (ver. 16). That Thabor and Hermon shall rejoice in Thy name: all day shall they rejoice, if they will, in Thy name; but if they will rejoice in their own name, they shall not rejoice all day: for they shall not continue in their joy, when they shall delight in themselves, and fall through pride. That they may rejoice all day, therefore, "they shall rejoice in Thy name, and in Thy righteousness shall they be exalted." Not in their own, but in Thine: lest they have a zeal of God, but not according to knowledge. For some are noted by the Apostle, that they have a zeal of God, but not according to knowledge, "being ignorant of God's righteousness, and going about to establish their own," and not rejoicing in Thy light, and thus "not submitting themselves unto the righteousness of God." And why? because "they have a zeal of God, but not according to knowledge." But the people who knoweth glad shouting (for the former err from want of knowledge, but blessed is the people not that knoweth not, but that knoweth glad shouting), whence ought it to shout, whence to rejoice, but in Thy name, walking in the light of Thy countenance? And it shall deserve to be exalted, but in Thy righteousness: let every man take away altogether his own righteousness, and be trembled: the righteousness of God shall come, and he shall be exalted, "and in Thy righteousness shall they be exalted."